Carboxylation process

ABSTRACT

A method of carboxylating indene, cyclopentadiene, fluorene and hydrocarbyl cyanide by contacting said compounds with carbon dioxide under substantially anhydrous conditions in the presence of a guanidine of the formula: WHERE R1 through R5 are hydrogen or alkyl of from one to five carbons and acidifying the resultant reaction mixture to form the carboxylic acid derivative and recovering said derivative therefrom.

States atent Patmore Y [4 Sept. 26, 1972 i CARBOXYLATION PROCESS PrimaryExaminer-Vivian Garner 72 Inventor: Edwin L. Patmore, Fishkill, N.Y.[73] Assignee: Texaco Inc., New York, N.Y. [57] ABSTRACT Filed! 1971 I Amethod of carboxylating indene, cyclopentadiene, [211' APPL NOJ 119,428fluorene and hydrocarbyl cyanide by contacting said compounds withcarbon dioxide under substantially Related US. Application Dataanhydrous conditions in the presence of a guanidine of [62] Division ofSer. No. 784,945, Dec. 18, 1968, thefmmula:

Pat. N0. 3,591,628. a [52] US. Cl ..260/514 B, 260/465 D, 260/515R 51Int. Cl. ..C07c 51/02, C07c 61/28 3 MW [58] Field of Search ..260/5 14 Bii I where R through R are hydrogen or alkyl of from [56] ReferencesC'ted one to five carbons and acidifying the resultant reac- UNlTEDSTATES PATENTS tion mixture to form the carboxylic acid derivative 2 716662 8/1955 C h t 1 26 /51 B and recovering said derivative therefrom.

, o ene a 5 Claims, N0 Drawings BACKGROUND OF INVENTION This inventionis in the field of art relating to the preparation of a carboxylic acidcompound derived from hydrocarbons and aralkyl cyanides.

In the past, the carboxylic acid derivatives of the reactantscontemplated herein were prepared by employing very expensive basessuch, as sodium, naphthalene, sodamide, and lithium salts such as butyllithium. The bases of the prior art being costly, rendered the processof preparing carboxylic acids of the type contemplated herein notpracticable from a commercial point of view even though the carboxylicproducts were very useful as chemical intermediates for the preparationof barbituates, synthetic lube oil additives and other chemicalcompounds.

1 SUMMARY OF INVENTION where R through R are hydrogen or alkyl of one tofive carbons, subsequently acidifying the resultant reaction mixture andrecovering the carboxylic acid derivative therefrom.

DETAILED DESCRIPTION OF THE INVENTION Specifically, the method comprisesforming a carboxylic acid compound of the group of R- HONindene-3-carboxylic acid, tricyclo [5.2.1.0 deca-3,8-diene-4,9-dicarboxylic acid and tricyclo [5.2.1.0deca-3,8-diene-4,9-dicarboxylic acid or fluorene-9-carboxylic acidcomprising contacting an organic reactant of RCI-I CN, indene,cyclopentadiene, or fluorene, respectively, where R is aralkyl of fromsix to 1 l carbons in the presence of a guanidine of the formula:

where R through R are as heretofore defined under substantiallyanhydrous conditions with carbon dioxide desirably in excess of thestoichiometric amount at a temperature between about and 250C.,preferably between 25 and 100C, under a carbon dioxide pressure of from1 to 500 atmospheres, preferably between 50 and 200 atmospheres,utilizing a mole ratio of base to organic reactant of between about 1:1and 20:1, preferably between 1:1 and :1. As a next step the reactionmixture is acidified to a pH of less than 6,

. preferably between about 1 and 3, and the resultant carboxylic productacid is recovered therefrom. Acidification is desirably conducted at atemperature of between about 5 and 35C.

A liquid solvent for the reaction would normally only be required toprovide liquid reaction mixture conditions for atmosphereic pressurecontactings. Suitable inert solvents are dimethyl sulfoxide, diphenylsulfoxide, dimethyl sulfone and dimethylformamide.

In addition to the indene, cyclopentadiene and fluorene reactantscontemplated herein are benzyl cyanide, v p-methylphenyl-acetonitrile,p-methylphenylacetonitrile, and p-propylphenylacetonitrile.

Specific examples of the carboxylic products contemplated herein inaddition to those previously mentioned are a-(p-methylphenyl)cyanoaceticacid, a-(pethylphenyl)cyanoacetic acid anda-(p-isopropylphenyl)cya.noacetic acid.

Specific examples of the acidifying acid contemplated herein are aqueousmineral acids of between about 4 and 96 wt. concentration such ashydroch1o ric acid, nitric acid, sulfuric acid, and hydrobromic acid.

The carboxylic acid product is recovered by standard means such as byextraction, distillation and combinations thereof.

By the term substantially anhydrous water contents less than 0.5 wt. areintended based on the reaction mixture.

The following examples further illustrate the invention but are not tobe construed as limitations thereof.

EXAMPLE I This example illustrates the preparation of indene-3-carboxylic acid from indene.

To a glass lined 0.5 liter rocker bomb there was charged 11.6 grains ofindene and 11.5 grams of 1,1,3,3-tetramethylguanidine. The resultantmixture has a water content less than 0.5 wt. The bomb was assembled andflushed with dry carbon dioxide and additional dry carbon dioxide wascharged to an initial pressure of 800 psig. The bomb was then rocked andheated at 98l02C. for a 5 hour period and during that time the pressureincreased to between 1000 and 1025 psig. The bomb was allowed to cooland was vented. The reaction mixture was worked up by acidifying withcold aqueous hydrochloric acid (200 mls. conc. I-ICl 100 grams of iceand 100 mls. of 6 molar I-ICl and the resultant acidic mixture wasextracted with ether (1X200 mls and 5x100 mls). The ether extracts werecombined and the combined extracts were further extracted with a 10 wt.aqueous sodium bicarbonate solution (SXIOO mls.). The bicarbonateextractions were cooled in ice water bath and made acidic with 6 molarl-ICl which was added until a pH of 3 was obtained. The yellow solidswere formed which were further extracted with ether (6x100 mls.). Theether solution was dried over anhydrous sodium sulfate followed bydrying over anhydrous calcium sulfate. The ether was stripped off on arotating evaporator to give a crude acidic product and the crude acidicproduct was recrystallized from benzene to yield 6.9 grams ofindene-3-carboxylic acid, corresponding to a yield of 43.3 mole percentyield basis indene reactant. The melting point of the indene carboxylicacid was l59-l6lC. (lit. l58l60C.). A mixture melting point of theproduct and a sample of known pure indene-3-carboxylic acid was notdepressed. The infrared and nuclear magnetic resonance spectra confirmedthe presence and structure of the indene-3-carboxylic acid product.

EXAMPLE II To a glass-lined, 0.5 liter pressure bomb, 14 grams of benzylcyanide and 13.8 grams of l,l,3,3-tetramethylguanidine were charged andthe bomb was assembled and flushed with dry carbon dioxide. Theresultant mixture had a water content less than 0.5 wt. Then additionaldry carbon dioxide was charged to an initial pressure of 900 psig. Thebomb was rocked and heated at 283 3C. and at 900-950 psig carbon dioxidepressure for 8 hours. The resultant reaction mixture was acidified andthe carboxylic product recovered in the manner described in Example I.The product weighed 0.5 grams and was identified asalpha-phenylcyanoacetic acid. The melting point of thealphaphenylcyanoacetic acid was 9l-94C. (lit. 92C.) and the infrared andnuclear magnetic spectra confirmed the structure.

EXAMPLE III To a 3-necked 100 ml., round-bottomed flask equipped with amagnetic stirrer, thermometer, gas sparger, heating mantle andcondenser, the exit of the condenser being connected to a mercurybubbler, there was charged 13.2 grams of cyclopentadiene and 23 grams ofl,1,3,3-tetramethylguanidine under atmospheric pressure conditions. Theresultant mixture had a water content less than 0.5 wt. Dry carbondioxide was bubbled under atmospheric pressure into the mixture of aperiod of 3 hours at 29-40C. The resultant product was acidified andworked up in accordance with Example I and 2.7 grams of tricyclo [5.2. l.O b] deca-3,8-diene-4,9-dicarboxylic acid (Thieles acid) representing ayield of 12.3 mole percent was obtained. The melting point of theproduct was l204C. (lit. 204-205C.) and an infrared spectral analysisconfirmed the production of Thieles acid.

EXAMPLE IV To a glass line, 0.5 liter bomb there was charged 26.4 gramsof cyclopentadiene and 46 grams of 1,1,33- tetramethyl guanidine. Thebomb was assembled and flushed with dry carbon dioxide. The watercontent in the resultant mixture was less than 0.5 wt. Then additionalcarbon dioxide was charged to an initial pressure of 850 psig. Themixture was rocked and heated to 73-77C. and at 900-925 psig carbondioxide pressured for 5 hours. The bomb was allowed to cool and ventedthrough a trap cooled with dry ice isopropyl alcohol. The resultantreaction mixture was acidified with cold aqueous HCl (200 rnls. of con.HCl+200 rnls. of water g. of ice) and the acidified mixture wasextracted with ether (1X200 mls.). At this point solids formed in theether extract and the ether extracts were filtered through a sinterglass filter, the solid residue on the filter washed several times withwater, air dried, and dried in a vacuum at room temperature to givetricyclo [5.2.1.0 deca-3,8-diene-4,9-dicarboxylic acid (9.2 grams)representing a yield of 20.9 wt. The product had a melting point of202208C. and an infrared spectrum confirmed structure.

The separated aqueous layer from acidification was worked up by etherextraction (6 l50 rnls.) followed by extraction of the ether with 10percent aqueous sodium bicarbonate (5X100 rnls.) and acidification ofthe sodium carbonate extracts with dilute hydrochloric acid to a pH ofabout 3 to give a second solid in the form of a precipitate having aweight of 7 grams. The second solid precipitate was tentativelyidentified as tricyclo-[5 .2. 1.0] deca-3,8-diene-5,S-dicarboxylic acidrepresenting a yield of 15.9 wt. of the cyclopentadiene reactant. Theinfrared spectral analysis of the second precipitate confirmed thestructure.

EXAMPLE V This example illustrates the criticality of the particularcombinations of reactants defined herein. Four runs were conducted inwhich the reactant or base material was substituted with substancesclosely related to the reactant or base contemplated herein. In Runs Aand C the overall procedure was that as essentially described in Example111. In Run B the overall procedure was that essentially described inExample IV. The water content in the initial reaction mixture was lessthan 0.5 wt.

1,1 ,3,3-tetramethylguanidine Polystyrene quaternary amine As can beseen from the foregoing table, variations in either closely relatedorganic reactants or base fails to result in the production of acarboxylic acid derivative under the contemplated conditions indicatingthe criticality of the particular combination of the claimed invention.

I claim:

1. A method of producing tricyclo [5.2.1.0 deca-3,8-diene-4,9-dicarboxylic acid and tricyclo [5.2.l.0

. 5 deca-3,8-diene-5,S-dicarboxylic acid comprising contacting,cyclopentadiene with carbon dioxide under a carbon dioxide pressure ofbetween about 1 and 500 atmospheres in the presence of a base of theformula:

and under substantially anhydrous conditions, at a temperature betweenabout and 250C. utilizing a mole ratio of base to organic reactant ofbetween about 1:1 and 20:1, acidifying the resultant mixture to a pH ofless than 6 and recovering said carboxylic acid therefrom, said Rthrough R being hydrogen or alkyl of from one to five carbons;

2. A method in accordance with claim 1 wherein said acidifying isconducted to a pH of between about 1 and 3 base is 1,1,3,3tetrarnethylguanidine, said carbon dioxide pressure is between about 50and 200 atmospheres,

and said temperature is between about 25 and C.

2. A method in accordance with claim 1 wherein said acidifying isconducted to a pH of between about 1 and
 3. 3. A method in accordancewith claim 2 wherein said acidifying acid is aqueous hydrochloric acid.4. A method in accordance with claim 1 wherein said carboxylic acid istricyclo (5.2.1.02,6) deca-3,8-diene-4,9-dicarboxylic acid, said base is1,1,3,3-tetramethylguanidine, said carbon dioxide pressure is aboutatmospheric and said temperature is between about 25* and 100*C.
 5. Amethod in accordance with claim 1 wherein said carboxylic acid is amixture of tricyclo (5.2.1.02,6) deca-3,8-diene-4,9-dicarboxylic acidand tricyclo (5.2.1.02,6) deca-3,8-diene-5,5-dicarboxylic acid, saidbase is 1,1,3,3-tetramethylguanidine, said carbon dioxide pressure isbetween about 50 and 200 atmospheres, and said temperature is betweenabout 25* and 100*C.